Dissecting Cellulitis of the Scalp

What is it?

Dissecting cellulitis of the scalp (also called perifolliculitis capitis abscedens et suffodiens or Hoffmann disease) is a rare, chronic inflammatory disease of the scalp. It causes painful lumps (nodules) and pockets of pus (abscesses) that are connected beneath the skin by tunnels (sinus tracts). Over time, this ongoing inflammation destroys hair follicles and leads to permanent hair loss with scarring (scarring or cicatricial alopecia).

Despite the word "cellulitis" in its name, it is not an infection in the usual sense. It belongs to a group of conditions called the follicular occlusion tetrad — together with hidradenitis suppurativa, severe (conglobate) acne, and pilonidal disease — in which hair follicles become blocked, rupture, and trigger intense inflammation.

Who is affected?

• Sex: The condition affects men far more often than women — roughly 9 out of 10 patients are male
• Age: It usually begins in early adulthood, most commonly between 20 and 40 years of age
• Skin type and ancestry: It is seen most often in people of African descent, though it can occur in any ethnic group
• Associated conditions: Many patients also have, or later develop, other follicular occlusion disorders — particularly hidradenitis suppurativa and severe acne
• Overall it is considered rare, but it is likely underrecognized because it can be mistaken for a simple infection

What causes it?

The exact cause is not fully understood, but the process begins with blockage of the hair follicles. A build-up of keratin (the protein that makes up hair and the outer skin) plugs and widens the follicle until it ruptures. The follicle contents spilling into the surrounding skin provoke an intense inflammatory reaction, forming the nodules, abscesses, and tunnels.

• Follicular occlusion, not primary infection, is the central event — bacteria found in the lesions are generally secondary and colonize already-damaged tissue
• Immune dysregulation: An overactive inflammatory response (involving immune messengers such as TNF-alpha and certain interleukins) sustains the disease and is the reason modern targeted treatments can help
• Shared mechanism with hidradenitis suppurativa: The two conditions are increasingly seen as closely related, which is why they often occur together and respond to similar treatments
• Contributing factors may include a genetic predisposition and, as in hidradenitis suppurativa, smoking and obesity

What are the clinical features?

The condition typically develops gradually and follows a long, relapsing course.

• Painful nodules and abscesses: Firm or fluctuant (fluid-filled) lumps appear, most often on the crown (vertex) and back (occiput) of the scalp
• Interconnecting sinus tracts: The lumps become linked by tunnels under the skin. A characteristic sign is that pressing on one area causes pus to emerge from a separate opening some distance away — the scalp feels soft and "boggy"
• Discharge: A recurrent flow of pus or blood-tinged fluid, sometimes with an odour
• Hair loss: As the follicles are progressively destroyed, patches of permanent, scarring baldness develop
• Chronic, relapsing course: Symptoms tend to flare and settle repeatedly over months and years

Psychosocial impact: Because it affects a highly visible area and can cause disfigurement, odour, and permanent hair loss, dissecting cellulitis often has a substantial emotional toll. Patients frequently experience embarrassment, low self-esteem, anxiety, and social withdrawal. This burden deserves attention alongside the physical treatment.

How is it diagnosed?

Diagnosis is usually clinical — based on the typical appearance and history.

• Clinical examination: The combination of boggy scalp nodules, interconnecting sinus tracts, discharge, and scarring hair loss is highly suggestive
• Dermoscopy (trichoscopy): Examination with a magnifying device can support the diagnosis, showing features such as yellowish structureless areas, dystrophic hairs, and follicular changes
• Swabs and cultures: Taken mainly to rule out a primary infection and to identify any secondary bacteria
• Skin biopsy: Occasionally performed to confirm the diagnosis or exclude other conditions
• What else it might be: A fungal scalp infection (tinea capitis/kerion), folliculitis decalvans, acne keloidalis nuchae, or an ordinary bacterial abscess can look similar and must be distinguished

What treatment options are available?

There is no guaranteed cure, and the disease tends to return when treatment stops, so the goal is long-term control and prevention of further scarring. Treatment is often combined and tailored to severity.

• Oral isotretinoin: A vitamin-A–derived retinoid taken by mouth; the most established treatment, often producing marked improvement, though relapse after stopping is common
• Antibiotics: Prolonged courses (particularly tetracyclines such as doxycycline, or a clindamycin–rifampicin combination) are used for their anti-inflammatory effect as much as for infection
• Corticosteroids: Injected directly into stubborn nodules, or a short oral course to calm a severe flare
• Biologic therapies: Injectable drugs that block specific inflammatory signals (such as TNF-alpha inhibitors like adalimumab) are increasingly used for moderate-to-severe or treatment-resistant disease
• Procedures: Draining large abscesses, laser hair removal to reduce the follicular load, photodynamic therapy, and — for severe, unresponsive cases — surgical removal of affected scalp
• Self-care: Gentle antiseptic scalp hygiene, and (as in hidradenitis suppurativa) stopping smoking and maintaining a healthy weight may help

Key points for patients

• Dissecting cellulitis is a chronic inflammatory condition, not a contagious infection, and it is not cancer
• Early treatment matters: because the hair loss it causes is permanent, starting treatment sooner can help limit lasting scarring
• The condition is often linked to hidradenitis suppurativa and severe acne — tell your doctor if you have these
• No single treatment works for everyone, and relapses are common — ongoing follow-up and combined treatment give the best results
• When to seek medical attention: See a dermatologist for any recurrent painful scalp lumps, discharge, or spreading hair loss. Seek review promptly if a long-standing area changes in appearance, hardens, or develops a non-healing sore
• The emotional impact is real — do not hesitate to raise it with your doctor, and consider psychological support if the condition affects your wellbeing